DYI compression fitting problems

I needed to replace a toilet shutoff valve that wouldn't turn completely off, and I bought a ball valve to do the job. The previous compression fitting had been on pretty tight, leaving indentations from the ferrule on the copper pipe. I wasn't sure whether that would be a problem, and for better or for worse, I cleaned everything up, sweated some silver solder onto the pipe, and sanded everything down. I think the effective indentation is less than it was before.

When I put the new valve in place, I placed only a drop of oil on the fitting threads, per the manufacturer instructions (no teflon tape or pipe dope). I'll mention that with the new valve, the ferrule sits a little closer to the end of the pipe than it did before. I also, for better or for worse, left about 1/32" space between the valve and the end of the pipe, according to a suggestion in an online forum (I know, I know, ...).

I hand tightened the compression fitting and then used channel locks and a wrench to go from snug to tight. Tiny little bit of seepage. I tightened some more. Still a bit of seepage. And so on at least one or two more times. At this point I'm not sure whether I should just keep tightening until the seepage stops. I know that's generally bad practice, but unless I can get this to work, I will probably have to sweat a little extension anyhow. Any suggestions?

It's risky, if the old compression fitting left a depression, to get a new one to seat properly. I don't think the silver solder helped any. Unless there's enough sticking out to cut that off, either soldering on a valve, or soldering on a fitting, then screwing one on, as was suggested, I think are your best choices.

I appreciate all the suggestions. In fact I do have enough length (2.5" from wall) to cut the pipe, and upon consideration, I would probably want to do that even if sweating, to avoid the risk of voids.

[hj, to answer your question, I used a hacksaw at an angle, and then split the ferrule.]

Soldering on a male adapter would obviously work well, except for the possible angle of the angle stop when properly screwed in. But perhaps it would make more sense to directly sweat an angle stop? Of course Home Depot doesn't carry 1/4 turn sweat angle stops (just multi-turn), and it would be nice to wrap this up today.

If I choose not to sweat, I'm wondering whether I should just go with SharkBite, having seen how a compression ferrule can damage the pipe. If I or somebody else needed to replace the SharkBite in 20 years, the pipe would still be intact.

Since you have the length, cut it off back so you've got nice-round pipe. If it has some paint or other crud on it, you'll have to clean that off. If you nicked the pipe at all with the hacksaw, and your new compression ferrule is in the same place, it's unlikely that it would seal.

As to a threaded connection, there's almost always enough 'play' where you can turn things to get it aligned and water-tight unless the threads are crappy, and it bottoms out.

I found a sweat angle stop, decided that was the superior solution, prepared the joint, and soldered it. Unfortunately, of the perhaps two-dozen joints I've ever soldered, this one is leaking. The joint was properly cleaned and fluxed, and the solder did flow into it (heating from underneath joint, solder melting on top), but perhaps there wasn't enough solder. Clearly I just don't have the confidence to sustain enough heat this close to the wall.

Ouch, I didn't think it looked this bad when I checked with a mirror. I wonder if my attempt to desolder sucked more of the solder deeper into the joint, but probably not, because I don't think the silver ever melted again. As far as I know, the proper way to fix this is to remove the valve, clean up and prep again, right? I can't just re-heat the joint and apply more solder, since there is presumably no flux left?

As it turns out, I'm also failing to apply enough heat to remove the valve. Might be time for me to call in one of your colleagues. Hopefully they won't want to cut out part of the wall.

You overheated it, you can tell from the discoloration. You want to move your torch all around the fitting until it gets hot enough, then you can likely just remove the torch and get enough solder to melt into the joint. By heating it only from one side, that side got too hot before the top would melt the solder. The guts of the valve are likely toast, too. Maybe, maybe not. If the length of the pipe is in good shape, not dinged up or pitted, then I'd probably just use a new compression stop.

Thanks again for all the suggestions. In this case I ended up calling one of your colleagues, and in the process found a good plumber that I can use in the future. Unsurprisingly, this was a piece of cake for him, except for the fact that the first valve was faulty. (Brass Craft leaking from the stem!? I actually thought I might have caused this by accidentally leaving the valve closed while soldering, but he tells me that wouldn't have damaged it. Or maybe Jim is right and I toasted it.) Fortunately I had purchased two of the same valve, so he took the first one off and put the second one on.

Terry, I wasn't sure if you were saying that the sweat angle stop sounded like a bad idea, or if it just sounded unusual in this case. I figured that a soldered ball valve should last a really long time, and still be replaceable in the future if necessary.

Jim, it's possible that I overheated the valve, but I think most of what you were seeing was just the result of the lighting. Even what I'm posting below looks a little discolored in the picture, but the discoloration is very minimal to the naked eye. And this is after initial soldering, attempted desoldering, resoldering, and removal. By comparison, the nut next to the valve also looks a little dark in the picture, but perfectly shiny in real life, and wasn't even on the valve during the soldering. Still, I'll admit that this was one of my worst soldering jobs.

Basically, a compression stop is faster and easier to install, so since time is money, plumbers typically install them verses soldering. Other than that, a compression, solder, or threaded valve all can work fine and last a long time...just depends on the situation.